BACKGROUND Objective of this study was to assess the degree to which preventive child health professionals (CHPs) identify and act upon psychosocial problems among young toddlers in the general population and to determine the concordance with parent-reported behavioural and emotional problems. Also, associations of psychosocial problems with socio-demographic factors, and (mental) health history of the toddlers were studied. METHODS CHPs examined a national sample of children aged 14 months and interviewed their parents during the routine health assessments. Identification of and action upon psychosocial problems by CHPs were registered. The Infant-Toddler Social and Emotional Assessment (ITSEA) was completed by the parents. Data were available on 701 Dutch 14-month-old toddlers. RESULTS In 7.6% of all toddlers, CHPs identified one or more psychosocial problems. Forty-seven percent of identified children were referred to another professional or received follow-up. Identification of psychosocial problems and subsequent action were 3-16 times more likely in children with clinical parent-reported problem behaviour according to the Dutch adapted version of the ITSEA. Also, past or current professional care for psychosocial problems was associated with the CHPs' identification or action. Associations with socio-demographic variables were weak. CONCLUSIONS The CHPs frequently identify psychosocial problems in 14-month-old toddlers, but they miss many cases of parent-reported problems as measured by a clinical ITSEA score. This general population study shows substantial room for improvement in the early identification of psychosocial problems in young toddlers.